A new approach to acoustic microscopy using multiplexed or coded imaging is proposed. This new approach is expected to offer improvements in signal-to-noise ratio over existing techniques and to make it possible to produce a small, compact microscope occupying only a few cubic centimeters (exclusive of electronics) and having no mechanical scanning. Images should be obtainable rapidly, with the goal being video rates. The main cost will be in the electronics, so it will be possible to have a large number of microscopes set up simultaneously and sharing the same electronics and display. Moreover, there will be no water gap or other coupling fluid, at least in the reflection version of the microscope, so shear waves can be used. The lower propagation velocity for shear waves should translate directly into improved spatial resolution. Specific aims of this grant include a detailed theoretical study of the proposed multiplexed acoustic microscope, development of techniques for fabrication of the required thin-film transducer array, and design and fabrication of a prototype electronics system. The end result will be a demonstration experiment to acquire actual images and verify the concept of the multiplexed acoustic microscope.